Build the types for serialization checks once at import time

[abdelq]

Summary

When using nested types with a lot of elements, profiling showed a lot of time was just spent on the type union per isinstance call. It gets costly.

I'd appreciate it if a patch release is made for this one :)

Test Plan

[codecov]

Codecov Report

❌ Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 71.16%. Comparing base (e298e13) to head (58ea98d).

Files with missing lines	Patch %	Lines
src/kfactory/serialization.py	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1045      +/-   ##
==========================================
- Coverage   71.19%   71.16%   -0.04%     
==========================================
  Files          74       74              
  Lines       15177    15181       +4     
  Branches     2960     2960              
==========================================
- Hits        10806    10804       -2     
- Misses       3441     3444       +3     
- Partials      930      933       +3     

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[sebastian-goeldi]

hmm, fair. wouldn't it be sufficient to build the union type once outside?